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if file is NOT empty, then append content to file

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# 1  
Old 11-08-2010
if file is NOT empty, then append content to file
hi people,

i have texts down.txt and down-new.txt and i want to check;

- if down-new.txt is NOT empty, then write date and its content to /home/gc_sw/down.txt

for example;

down.txt:
Code:
AAAA
SSSS

down-new.txt:
Code:
123
456

and after checking down-new.txt is NOT empty, down.txt should be:
Code:
AAAA
SSSS
 
20101108-1300
123
456

please write your codes in awk.

thx Smilie
Last edited by gc_sw; 11-08-2010 at 08:37 AM..
# 2  
Old 11-08-2010
Somethig like this,
Code:
awk '{print}' down-new.txt >> /home/gc_sw/down.txt

# 3  
Old 11-08-2010
Question Why the 'awk' requirement
Whenever someone specifies how a solution is to be done, it is often because this is not a real problem but rather a homework problem.
Please explain/clarify.
# 4  
Old 11-08-2010
try:
Code:
[ ! -s file ]

# 5  
Old 11-08-2010
pravin27:
thanks but where is the check of if file is not zero and date?

joeyg;
bacause my all code block is in awk, i prefer it rather than other ways. if there are alternatives you can surely express it Smilie

Scrutinizer;
thanks dude but can you please write the whole code? i have tried some combinations with if, !-s, NF, NR, etc.. but no results Smilie
# 6  
Old 11-08-2010
It was not awk but rather a standard shell test to see if a file is not empty:
Code:
if [ ! -s down-new.txt ]; then
  date >> down.txt
  cat down-new.txt >> down.txt
fi

In awk you can something like this:
Code:
awk 'END{if(!NR)print "empty"}' file

But I think it becomes more complicated..
# 7  
Old 11-08-2010
With awk you can do something like:
Code:
if(system("[ -s down-new.txt ]") == 0){
  # file is NOT empty
}
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